Speed responsive apparatus



Jime 6, 1933.

F. H. NICHOLSON SPEED RESPONSIVE APPARATUS Filed Jui 2 1951 L 2 Brake YMa nezl C D 1 Y X E Bmlie (271211 0111129 Y Mgg'nez. .D o Y Relay BelaP101; -up 2 5 Cazpem b 9 1,1 11 b xa low C VCI \/('2 V65 SPPQd RelayRelease *7 1 72 17297 FL 5 Relay P101-Zlp- ,9 g Relag CUPPQHZ RelayHelease' 9 4 e b 1,1- p253 70 1kg]? kelag CI Speed Current Relay zme PiCli up Hg. 4.

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Patented June 6, 1933 UNITED STATES PATENT OFFICE FRANK H. NICHOLSON,OF'EDGEWOOD, PENNSYLVANIA, ASSIGNOR TO THE UNION SWITCH & SIGNALCOMPANY, OF SWISSVALE, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA SPEEDRESPONSIVE APPARATUS Application filed July 20, 1931. Serial110,551,967.

My invention relates to speed responsive apparatus. I

One object of my invention is the provision of novel and improved speedresponsive apparatus which is simple, rugged, reliable, and inexpensiveto manufacture, and which at the same time is highly sensitive to speedvariations both accelerating and decelerating.

I will describe two forms of apparatus embodying my invention, and willthen point out the novel features thereof in claims.

In the accompanying drawing, Fig. 1 is a diagrammatic view illustratingone form of apparatus embodying my invention. Fig. 2 is a similar viewshowing a modified form of the apparatus illustrated in Fig. 1, and alsoembodying my invention. Figs. 3, 4 and 5 are diagrams, showinggraphically, the operating characteristics of a portion of the apparatusillustrated in Figs. 1 and 2.

Similar reference characters refer to similar parts in each of theseveral views.

Referring first to Fig. 1, speed responsive apparatus embodying myinvention is here shown as comprising a cam member B and a cam followerA which cooperates with the cam member B. The cam member B is ofsuitable electrical conducting material, such as brass, and is intendedto be operatively connected with any body or device whose linear orangular speed it is desired to measure, in such manner that the speed ofrotation of the cani member will be proportional at all times to thespeed of the body or device. For example, assuming that it is desired tomeasure the speed of a locomotive or car, the cam member B may beconnected directly with, or geared to, an'axle or other convenient partof the running gear of the locomotive or car, in which event the speed'of rotation of the cam member will increase or decrease as the speed ofthe locomotive or car increases or decreases.

The cam follower A, which is likewise constructed of suitable electricalconducting material, such as brass, is pivotally supported at one end ona suitable pivot indicated at 1 in the drawing, and has its free endshown, is such that its peripheral surface is substantially in the formof a portion of a spiral, the two ends of the spiral surface beingjoined by a radially extending portion 2. With this construction, itwill be seen that if the cam member B is rotated in the directionindicated by the arrow, each time the radially extending portion 2passes the end of the cam follower A, the follower will leave thesurface of the cam member for a substantially fixed interval of time,the length of which depends upon'the mass of the follower A and the pullof spring S. It will also be seen that since the time interval duringwhich the cam follower is out of engagement with the cam member duringeach revolution of the cam member is substantially fixed, the timeinterval during which the cam follower remains in engagement with thecam member during each revolution will decrease as the speed of rotationof the cam member increases.

Secured to the cam member B, and in electrical contact therewith, is aslip ring 4 which cooperates with a brush 5. The function of the slipring 4 and the brush 5 will become apparent as the description proceeds.

The apparatus also includes a reactance C v and an electro-responsiveindicating device, here shown as a relayD. The reactance C and the relayD are connected in series in a circuit which passes from terminal X of asuitable source of current, not shown in the drawing, through camfollower A, cammenn ber B, slip ring 4, brush 5, reactance C, and thewinding of relay 1) to the other terminal Y of the source. Connected inmultiple with the reactance C and relay D in the circuit just traced, isan asymmetric unit R which is so disposed that it will offer its highestresistance to current which tends to flow through the branch pathincluding this unit from terminal X to terminal Y of the source.

The operation, as a whole, of the apparatus thus far described is asfollows: When cam member B is rotated, the previously described coactionbetween the cam member and the cam follower will cause the circuit forrelay D and reactance C to be opened for a fixed interval of time duringeach revolution of the cam member, and to be closed for a variableinterval of time the length of which is inversely proportional to somefunction of the speed of rotation of cam member B. Each time thecircuitfor relay D and reactance C is opened, the current in the windingof relay D will start to decrease, but this current will not immediatelydecrease to zero because the energy stored in this winding and inreactance C will cause a circulating current to flow in the closedcircuit formed by reactance C, the winding of relay D, and asymmetricunit R, and this circulating current will delay the decay of current inthe winding of relay D. Similarly, each time the circuit for reactance Cand relay D is reestablished, the current in the winding of relay D willstart to build up, the rate of growth of this current being determinedby the inductance of the circuit. For a given proportioning of theparts, the growth and decay of the current in the winding of relay Dwhen cam member B is rotated at a relatively low speedis indicated bythe curve 7 shown in Fig. 3. Referring to this figure, the line a-b ofthe curve 7 indicates the magnitude of the current in the winding ofrelay D when cam member B is at rest. When the circuit for reactance Cand relay D is first opened, due to the cam follower A leaving thesurface of cam member B, the current in the winding of relay D will fallalong the line b-c. When this circuit is next reestablished by the camfollower reengagmg the cam member, the current in the winding of relay Dwill .build up along the.

line cb It will be obvious that the final value of the current in thewinding of relay D will depend upon the time during which cam follower Aremains in engagement with cam member B. The next succeeding revolutionof cam member B will cause the current in the winding of relay D totrace the line b -c b etc.

It will be seen that if relay D is constructed to have a pick-up valueas indicated by the line 8 in Fig. 3, and a release value as indicatedby the line 9, relay D will remain picked up, and hence will hold itsfront contact 6 closed, as long as cam member B rotates below apredetermined speed.

Referring now to Fig. 4, I have here shown a curve 10 which indicatesthe growth and decay of the current in the winding of relay D when thecam member B is rotated at a relatively high speed. It will be notedfrom an inspection of this curye that the open circuit interval duringwhich the current in the winding of relay D is decreasing, is the samelength as when the cam member B was rotating at the slower speed, butthat the closed circuit interval is considerably shorter. It will alsobe noted, that the current in the winding of relay D never reaches thevalue at which this relay will pick up and close its front contact.

It follows from the foregoing that by properly selecting the electricaland mechanical characteristics of the elements of the apparatus, it ispossible to cause relay D to open and close its front contact 6 at anydesired speed of rotation of cam member B.

Referring now to Fig. 5, the curve 11 here shown indicates the variationwhich takes place in the maximum or peak value of the current in thewinding of relay D as the speed of rotation of cam member B varies, andthe curve 12 indicates the variation in the minimum value of the currentin the winding of relay D as the speed of rotation of cam member Bvaries. From an inspection of these curves, it will be seen that if itis desired to have the relay operate its contact at a certain definitespeed of rotation of cam member B, this result may be accomplished byconstructing the relay in such manner that at the desired speed, itspick-up and release values will fall on these curves. For example,assuming that it is desired to have relay D operate its contact at thespeed indicated by the vertical line 13 in Fig. 5, this may be done byconstructing relay D to have pick-up and release values corresponding tothe points where line 13'crosses the curves 11 and 12.

Relay D may be utilized to control any suitable electro-responsivedevice in such manner that the device will occupy one condition whenthis relay is energized, and another condition when this relay isdeenergized. For example, if the apparatus is mounted on a locomotive insuch manner that the'speed of rotation of cam member B varies withthe'linear speed of the locomotive, relay D may be utilized to control aspeed governing device for the locomotive.

As here shown, relay D controls a brake controlling magnet E whichapplies the brakes on the locomotive when this magnet becomesdeenergized. The circuit for magnet E is carried over front contact 6 ofrelay D and it will be apparent, therefore, from the foregoing, that aslong as the speed of the locomotive is below some predetermined speed,magnet E will be energized, but that if the speed of the locomotiveincreases beyond this speed, magnet E will-become deenergized, thusenforcing a low speed limit on the locomotive. It should be definitelyunderstood, however, that apparatus embodying my'invention is in no waylimited to this particular use.

Referring now again to Fig. 1, it should be pointed out that if the cammember B is connected to a device which may rotate in either direction,such for example, as a reversible motor, the connection between themotor and the cam member will be so designed that the cam member willrotate in the same direction for either direction of rotation of themotor.

Under some conditions, it is undesirable,-

to carry the circuit for reactance C and relay D through cam member B.When this'is the case, the apparatus may be constructed in the mannerillustrated in Fig. 2. As here shown, an inertia member AA, the mass ofwhich is determined largely by the mass of an integral cylinder M, 'ispivotally mounted for rotation about a suitable pivot indicated at 14 inthe drawing, the pivot 14 being concentric with the axes of the cylinderM. The inertia member AA is connected with the cam follower A by aspring T which constantly urges the inertia member toward the positionin which a contact finger 15 attached to the right-hand end of theinertia member engages a contact member 16 attached to the cam followerA. The circuit for relay D as here shown, is from terminal X, throughinertia member AA, contact 15-16, cam follower A, and then as previouslydescribed in connection with Fig. 1, to terminal Y.

With the apparatus constructed in the manner shown in Fig. 2, each timethe radial portion 2 of the cam member B passes the end of the camfollower A, a cam follower will leave the surface'of the cam member fora fixed interval of time in the manner previously described. When thecam follower leaves the surface of the cam member, the spring T willbecome stressed and will exert a downward pull on the inertia member AAbut due to the inertia of the inertia member, the. inertia member willlag behind for a fixed interval of time, and during this interval oftime, contact 1516 will be open. By properly proportioning the massofthe inertia member AA, the tension of spring T, the mass of camfollower A, and the tension of spring S, the contact 15-16 may bemade-to open and close the circuit for reactance C and relay D insubstantially I the same manner as cam follower A and cam member Binterrupted this circuit in Fig.

1. The operation of the electrical portion be obtained without thisreactance by constructing relay D to have a reactance which is theequivalent of the combined reactance of reactance C and its own winding.

Although I have herein shown and de-,

by the body for periodically interrupting an electrical circuit forsubstantially uniform intervals which recur at a frequency which varieswith the speed of the body, an electro-responsive indicating device, anelectrical circuit controlled by said means and including saidindicating device, and an asymmetric unit connected in multiple withsaid device.

2. Apparatus for indicating the speed of a movable body comprising meanscontrolled by the body for periodically interrupting an electricalcircuit for substantially uniform intervals which recur at a frequencywhich varies with the speed of the body, an electroresponsive indicatingdevice, a reactance; an electrical circuit including said means, saidindicating device and said reactance, and an asymmetric unit connectedacross said reactance and said electro-responsive device in saidcircuit.

3. Speed responsive apparatus comprising a rotatable cam member ofelectrical con ducting material, a cam follower of electrical conductingmaterial biased into engagement with said cam member, said cam memberand said cam follower being so constructed that said follower will moveout of engagement with said cam member for a substantially fixedinterval of time during each revolution of said camimember, anelectroresponsive indicating device, an electrical circuit for saiddevice including said cam member and said cam follower, and anasymmetric unit connected in multiple with said device in said circuit.

4. Speed responsive apparatus comprising a rotatable cam member ofelectrical conducting material, a cam follower of electrical conductingmaterial biased into engagement with said cam member, said cam memberand said cam follower being so constructed that said follower will moveout of engagement with said cam member for a substantially fixedinterval of time during each revolution of said cam member. anelectro-responsive indicating device, and an inductive electricalcircuit for said device controlled by the contact formed by said cammember and said cam follower.

5. Speed responsive apparatus comprising a rotatable cam member ofelectrical conducting material, a cam follower of electrical conductingmaterial biased into engagement 6 with said cam member, said cam memberand said cam follower being so constructed that said follower will moveout of engagement with said cam member for a substantially fixedinterval of time during each rev- 10 olution of said cam member, anelectro-responsive indicating device, means controlled by said cammember and said cam follower for supplying current to said device, andan asymmetric unit connected across said device.

6. Speed responsive apparatus comprising a rotatable cam member ofelectrical conducting material, a cam follower pf electrical conductingmaterial biased into engage ment with said cam member, said cam mem- 2ber and said cam follower being so constructed that said follower willmove out of engagement with said cam member for a substantially fixedinterval of time during each revolution of said cam member, anelectroresponsive indicating device, a reactance; an electrical circuitincluding said cam follower, said cam member, said indicating device,and said reactance, and an asymmetric unit connected in multiple withsaid reactance and said indicating device in series in said circuit.

7. Speed responsive apparatus comprising a rotatable cam membersubstantially in the form of a portion of a spiral, a cam followerbiased into engagement with said cam member, an electro-responsiveindicating device, an asymmetric unit, and means controlled by said cammember and said cam follower for supplying to said device and saidasymmetric unit connected in multiple current which is periodicallyinterrupted for substantially uniform intervals which recur at afrequency which varies with the s eed of rotation of the cam member, 458. peed responsive apparatus comprising a rotatable cam membersubstantially in the form of a portion of a spiral, a cam follower,means for biasing said cam follower into engagement with said cammember, a relay, a reactance, an asymmetric unit, a closed circuitformed by said asymmetric unit connected in multiple with said relay andsaid reactance in series, and means controlled by said cam member andsaid cam follower for supplying to said closed circuit current which isperiodically interrupted for substantially uniform intervals which recurat a frequency which varies with the speed of rotation of said cammember. 3

9. Speed responsive apparatus comprising a rotatable cam membersubstantially in the form of a portion of a spiral, a cam follower,means for biasing said cam fol- 65 lower into engagement with said cammemcircuit current the magnitude of which is periodically decreased forsubstantially uniform intervals which recur at a frequency which varieswith the speed of the body.

10. Speed responsive apparatus comprising a rotatable cam membersubstantially in the form of a portion of a spiral, a cam follower,means for biasing said cam follower into engagement with said cammember, a contact member attached to said cam follower, a spring, apivoted inertia member provided with a contact finger and biased bymeans of said spring to the position in which said contact fingerengages said contact member, a relay, and an inductive cir-. cuit forsaid relay controlled by the contact formed b said fixed contact andsaid contact mem er.

11. Speed responsive apparatus comprising a rotatable cam membersubstantially in the form of a portion of a spiral, a cam follower,means for biasing said cam follower into engagement with said cammember, a contact member attached to said cam follower, a spring, apivoted inertia member provided with a contact finger and biased bymeans of said spring to the position in which said contact fingerengages said contact member, a relay, an asymmetric unit, and meanscontrolled by the contact formed by said contact linger and said contactmember for supplying current to said relay and said asymmetric unitconnected in multiple.

12. Speed responsive apparatus comprising an oscillating member, aninertia member operativzly connected with said oscillating member, acontact controlled by said oscillating member and said inertia member,an asymmetric unit; an electro-responsive device, and a circuitcontrolled by said contact and including said asymmetric unit and saiddevice connected in multiple.

13. Speed responsive apparatus comprising an oscillating member, aninertia member operatively connected with said oscillating member, acontact controlled by said oscillating member and said inertia member, areactance, an asymmetric unit, an electroresponsive device, and acircuit controlled by said contact and including said asymmetric unitconnected in multiple with said reactance and said electro-responsivedevice connected in series. V

14. Apparatus for indicating the speed of a body comprising a memberwhich is oscillated at a speed which is proportional to the speed of thebody, a contact member carried by said oscillated member, a spring, aninertia member provided with a contact finger and biased by means ofsaid spring to the position in which said contact finger engages saidcontact member, and an electro-responsive device controlled by thecontact formed by said contact finger and said contact member.

15. Apparatus for indicating the speed of a body comprising a memberwhich is oscillated at a speed which is proportional to the speed of thebody, a contact member carried by said oscillated member, a spring, aninertia member provided with a contact finger and biased by means ofsaid spring to the position in which said contact finger engages saidcontact member, an electroresponsive device, an asymmetric unit, and acircuit controlled by the contact formed by said contact finger and saidcontact member and including said asymmetric unit and saidelectro-responsive device connected in multiple.

16. Apparatus for indicating the speed of a body comprising a memperwhich is oscillated at a speed which is proportional to the speed of thebody, acontact member carried by said oscillated member, a spring, aninertia member provided with a contact finger and biased by means ofsaid spring to the position in which said contact finger engages saidcontact member, an electroresponsive device, an asymmetric unit, areactance, and a circuit controlled by the contact formed by said,contact finger and said contact member and including said asymmetricunit connected in multiple with said reactance and saidelectro-responsive device connected in series.

17. Speed responsive apparatus comprising a rotatable cam membersubstantially in the form of a portion of a spiral, a cam follower,means for biasing said cam follower into engagement with said cammember, a contact member attached to said cam follower, a spring, apivoted inertia member provided with a contact finger and biased bymeans of said spring to the position in which said contact fingerengages said contact member, a relay, a reactance, an. asymmetric unit,and means controlled by said contact finger and said contact member forsupplying current to a closed circuit including said asymmetric unitconnected in multiple with said reactance and said relay connected inseries.

18. Apparatus for controlling the speed of a movable body comprising acontact, means connected with the body for controlling said contact insuch manner that when the body'is at rest in any position the contactwill be closed but that when the body is moving said contact will becomeperiodicallyopened for substantially uniform intervals which recur at afrequency which varies with the speed of the body, an

means connected with the body for controlling said contact in suchmanner that when the body is at rest in any position the contact will beclosed but that when the body is moving said contact will becomeperiodically opened for substantially uniform intervals which recur at afrequency which varies with the speed of the body, an electro-responsivedevice, an electrical circuit controlled by said contact and includingsaid device, an asymmetric unit connected in multiple with said deviceand means for controlling the speed of said body controlled by saiddevice.

20. Apparatus for controlling the speed of a movable body comprising acontact, means connected with the body for controlling said contact insuch manner that when the body is at rest in any position the contactwill be closed but that when the body is moving said contact will becomeperiodically opened for substantially uniform intervals which recur at afrequency which varies with the speed of the body, an electro-responsivedevice, a reactance; an electrical circuit including said contact, saidelectro-responsive device, and said reactance; an asymmetric unitconnected across said reactance and said electro-responsive device insaid circuit, and means for controlling the speed of said bodycontrolled by said device.

21. Apparatus for controlling the speed of a vehicle comprising acontact, means connected with the vehicle for controlling said contactin such manner that when the. vehicle is at rest in any position saidcon tact will be closed but that whenthe vehicle is moving said contactwill become periodically opened for substantially uniform intervalswhich recur at a frequency. which varies with the speed of the vehicle,a relay adjusted to release its armature when the average value of thecurrent in its winding decreases below a predetermined value, anelectrical circuit controlled by said contact and including the windingof said relay, and a brake controlling magnet for the vehicle controlledby a front contact of said relay.

22. Apparatus for controlling the speed of a vehicle comprising acontact, means connected with the vehicle for controlling said contactin such manner that when the vehicle is at rest in any position saidcontact will be closed but that when the vehicle is moving said contactwill become periodically opened for substantially uniform intervalswhich recur at afrequency which varies with the speed of the vehicle, arelay adjusted to release its armature when the average value of thecurrent in its winding decreases below a predetermined value, anelectrical circuit controlled by said contact and including the windingof said relay, an asymmetric unit connected in multiple with the windingof said relay, and a brake controlling magnet for the vehicle controlledby a front contact of said relay.

23. Apparatus for controlling the speed of a vehicle comprising acontact, means connected with the vehicle for controlling said contactin such manner that when the vehicle is at rest in any position saidcontact will be closed but that when the vehicle is moving said contactwill become periodically opened for substantially uniform intervalswhich recur at a frequency which varies with the speed of the vehicle, arelay adjusted to release its armature when the average value of thecurrent in its winding decreases below a predetermined value, areactance; an electrical circuit including said contact, the winding ofsaid relay, and said reactance; an asymmetric unit connected across saidreactance and the winding of said relay in said circuit, and a brakecontrolling magnet for the vehicle controlled by a front contact of saidrelay.

In testimony whereof I aflix my signature.

FRANK H. NICHOLSON.

